<strong>Purpose:</strong><span style="font-family:Verdana;"> This study aims to evaluate the treatment plans of Volumetric-mo</span><span style="font-family:;" "=&qu...<strong>Purpose:</strong><span style="font-family:Verdana;"> This study aims to evaluate the treatment plans of Volumetric-mo</span><span style="font-family:;" "=""><span style="font-family:Verdana;">dulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) techniques for </span><span style="font-family:Verdana;">cervical-thoracic esophageal cancers. </span><b><span style="font-family:Verdana;">Methods</span></b> <b><span style="font-family:Verdana;">and</span></b> <b><span style="font-family:Verdana;">Materials:</span></b><span style="font-family:Verdana;"> Sixty patients were retrospectively identified. Several parameters</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">were evaluated based on target conformity and dose-volume histograms of organs at risk (lung, spinal cord, and heart). A phantom for time comparison was also assessed for each plan. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> The IMRT plans (5f-IMRT: V95% = </span></span><span style="font-family:Verdana;">99.4 ± 0.3, 7f-IMRT: V95% = 99.8 ± 0.1) results in better PTV coverage than RA plans (Single-arc: V95% = 95.8 ± 3.2, Double-arc: V95% = 95.4 ± 2.3). The target dose conformity of the 5f-IMRT plan was inferior to all plans (CI = 70.4 ± 7.1). The Single-arc plan achieved the best conformity (CI = 72.5 ± 4.6), whereas the Double-arc plan (CI = 72.1 ± 5.1) was slightly inferior to the Single-arc plan but superior to the 7f-IMRT plan (CI = 71.7 ± </span><span style="font-family:Verdana;">8.6). The total MU was reduced by 42.1% in VMAT plan. The average MU needed to deliver the dose of 60 Gy for Single-arc (423.5 ± 52.1 MU) was found to be the least. Similarly, the average MU for the 5f-IMRT, 7f-IMRT and Double-arc were 868.2 ± 182.0 MU, 870.0 ± 225.3 MU and 548.8 ± 47.2 MU, respectively. The delivery time in VMAT plans</span><span style="font-family:Verdana;"> was</span><span style="font-family:Verdana;"> reduced from 193.8</span><span style="font-family:Verdana;"> seconds to 99.2</span><span style="font-family:Verdana;"> second</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> by around 48.8% compared to IMRT</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">plans.</span><b><span style="font-family:Verdana;"> Co</span><span style="font-family:Verdana;">nclusion:</span></b><span style="font-family:Verdana;"> For similar PTV parameters, VMAT delivers a lower dose t</span><span style="font-family:Verdana;">o organs at risk than IMRT in a shorter time, and this has warranted clinical implementation.</span></span>展开更多
Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not ...Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not be taken into account during that calculation process. During IMRT routine practical work, it is noticed that there are some non-delineated normal tissue volumes that received un-aimed dose. Aim: The purpose of this study was to study the effect of unusually delineated normal volumes in IMRT treatment for left sided breast cancer. Method: Ten left sided breast cancer patients were planned with IMRT inverse planning system. The unusually delineated normal volumes were delineated and taken into account in IMRT dose constraints as an Organ at Risk. Doses received by that volume were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that doses received by the unusually delineated volume when they were delineated and taken into account in IMRT dose constraints were significantly higher than when they were not. Conclusions: The results showed that for IMRT planning technique used for treating left-sided breast cancer, all of the normal tissues/structures that are closed to the treatment targets must be delineated and taken into account in the IMRT planning dose constraints.展开更多
文摘<strong>Purpose:</strong><span style="font-family:Verdana;"> This study aims to evaluate the treatment plans of Volumetric-mo</span><span style="font-family:;" "=""><span style="font-family:Verdana;">dulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) techniques for </span><span style="font-family:Verdana;">cervical-thoracic esophageal cancers. </span><b><span style="font-family:Verdana;">Methods</span></b> <b><span style="font-family:Verdana;">and</span></b> <b><span style="font-family:Verdana;">Materials:</span></b><span style="font-family:Verdana;"> Sixty patients were retrospectively identified. Several parameters</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">were evaluated based on target conformity and dose-volume histograms of organs at risk (lung, spinal cord, and heart). A phantom for time comparison was also assessed for each plan. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> The IMRT plans (5f-IMRT: V95% = </span></span><span style="font-family:Verdana;">99.4 ± 0.3, 7f-IMRT: V95% = 99.8 ± 0.1) results in better PTV coverage than RA plans (Single-arc: V95% = 95.8 ± 3.2, Double-arc: V95% = 95.4 ± 2.3). The target dose conformity of the 5f-IMRT plan was inferior to all plans (CI = 70.4 ± 7.1). The Single-arc plan achieved the best conformity (CI = 72.5 ± 4.6), whereas the Double-arc plan (CI = 72.1 ± 5.1) was slightly inferior to the Single-arc plan but superior to the 7f-IMRT plan (CI = 71.7 ± </span><span style="font-family:Verdana;">8.6). The total MU was reduced by 42.1% in VMAT plan. The average MU needed to deliver the dose of 60 Gy for Single-arc (423.5 ± 52.1 MU) was found to be the least. Similarly, the average MU for the 5f-IMRT, 7f-IMRT and Double-arc were 868.2 ± 182.0 MU, 870.0 ± 225.3 MU and 548.8 ± 47.2 MU, respectively. The delivery time in VMAT plans</span><span style="font-family:Verdana;"> was</span><span style="font-family:Verdana;"> reduced from 193.8</span><span style="font-family:Verdana;"> seconds to 99.2</span><span style="font-family:Verdana;"> second</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> by around 48.8% compared to IMRT</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">plans.</span><b><span style="font-family:Verdana;"> Co</span><span style="font-family:Verdana;">nclusion:</span></b><span style="font-family:Verdana;"> For similar PTV parameters, VMAT delivers a lower dose t</span><span style="font-family:Verdana;">o organs at risk than IMRT in a shorter time, and this has warranted clinical implementation.</span></span>
文摘Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not be taken into account during that calculation process. During IMRT routine practical work, it is noticed that there are some non-delineated normal tissue volumes that received un-aimed dose. Aim: The purpose of this study was to study the effect of unusually delineated normal volumes in IMRT treatment for left sided breast cancer. Method: Ten left sided breast cancer patients were planned with IMRT inverse planning system. The unusually delineated normal volumes were delineated and taken into account in IMRT dose constraints as an Organ at Risk. Doses received by that volume were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that doses received by the unusually delineated volume when they were delineated and taken into account in IMRT dose constraints were significantly higher than when they were not. Conclusions: The results showed that for IMRT planning technique used for treating left-sided breast cancer, all of the normal tissues/structures that are closed to the treatment targets must be delineated and taken into account in the IMRT planning dose constraints.
